CVE-2024-39908VulnerabilityPublished 16 Jul 2024Updated 3 Nov 2025

CVE-2024-39908: ruby rexml · Uncontrolled Resource Consumption

Affects ruby rexmlSource CVE Database V5

Not known to be exploited · CVSS 4.3 Medium : upgrade to 3.3.2 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

4.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 1.4% chance of exploitation in 30 days – higher than 73% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 3.3.2

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 16 Jul 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade ruby rexml to 3.3.2.

Affected software

Product	Affected	Fixed in
RubyGemsrexml`pkg:gem/rexml`Other threats	Affected <3.3.2	Fixed in 3.3.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The primary mitigation is to upgrade the REXML gem to version 3.3.2 or later, which contains patches addressing the uncontrolled resource consumption issue. Organizations should audit their Ruby application dependencies to identify and update vulnerable REXML versions promptly. For environments where upgrading is not immediately feasible, it is critical to implement strict input validation and sanitization to prevent parsing of untrusted or malformed XML data. Employing XML parsing libraries with built-in protections against resource exhaustion or switching to alternative XML parsers with better security profiles may also be considered. Additionally, rate limiting and resource usage monitoring on services that parse XML can help detect and mitigate potential DoS attempts. Incorporating application-layer firewalls or XML gateways that filter suspicious XML payloads can provide an additional security layer. Finally, educating developers and system administrators about the risks of parsing untrusted XML and enforcing secure coding practices will reduce exposure.

Description

REXML is an XML toolkit for Ruby. The REXML gem before 3.3.1 has some DoS vulnerabilities when it parses an XML that has many specific characters such as `<`, `0` and `%>`. If you need to parse untrusted XMLs, you many be impacted to these vulnerabilities. The REXML gem 3.3.2 or later include the patches to fix these vulnerabilities. Users are advised to upgrade. Users unable to upgrade should avoid parsing untrusted XML strings.

Impact

For European organizations, this vulnerability primarily threatens the availability of Ruby-based applications that utilize the REXML gem for XML processing. Organizations that accept or process XML data from untrusted or external sources—such as web services, APIs, or integrations with third-party systems—are particularly vulnerable. Exploitation could lead to denial-of-service conditions, causing service outages or degraded performance, which may disrupt business operations or critical services. This is especially concerning for sectors relying on Ruby applications for customer-facing services, financial transactions, or infrastructure management. While the vulnerability does not compromise data confidentiality or integrity, the availability impact could lead to reputational damage, financial loss, and regulatory scrutiny under European data protection and operational resilience regulations. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially as attackers often develop exploits following public disclosure.

CWE-400Uncontrolled Resource Consumption (opens in a new tab)
Class weaknessLikelihood of exploit: High
The product does not properly control the allocation and maintenance of a limited resource.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place.
Architecture and Design
Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or; uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed.
Architecture and Design
Ensure that protocols have specific limits of scale placed on them.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
XML Ping of the Death (opens in a new tab)
Regular Expression Exponential Blowup (opens in a new tab)
Sustained Client Engagement (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 3 Nov 2025, 22:20 UTC

WeaknessesCWE-400

Technical details

References

Community reviews

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